#include<bits/stdc++.h> using namespace std; int main() { int n; cin>>n; if(n==0) cout<<"YES"; else cout<<"NO"; return 0; }

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a;
    cin>>a;
    if(a==0) cout<<"YES";
    else cout<<"NO";
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a;
    cin>>a;
    if(!!a)
    {
        cout<<"NO";
    }
    else
    {
        cout<<"YES";
    }
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
int main ()
{
    int w;
    cin>>w;
    if (w==0)
    {
        cout<<"YES";
    }
    else
    {
        cout<<"NO";
    }
    return 0;
}